Oil spills on a body of water present major ecological problems. Ships and offshore installations are two of the biggest sources of this problem because the ships and installations dump more than 500,000 tons of oil into the marine environment every year. To combat the problem, an increasing number of national, regional and international strategies have been and are being developed. However, these present strategies and the associated sporadic surveillance methods are proving inadequate to detect oil in marine environments.
As a result, the Convention for the Protection of the Marine Environment of the Northeast Atlantic (the OSPAR Convention) is developing programs and measures for identifying emissions and discharges of substances. The goal of OSPAR is to develop the required equipment for implementing and enforcing the programs and measures adopted under this strategy. Accordingly, regulatory enforcement requires around-the-clock surveillance. However, using existing surveillance methods to achieve these goals is cost prohibitive, unreliable and ineffective.
Currently, aircraft and ships may be used in oil-spill detection. Aircraft have the capability of investigating large areas. However, the use of aircraft is expensive. A ship is a more cost-effective way to detect oil spills. A ship may be equipped with radar having adjustable filters to control sensitivity towards haze, rain and so-called sea-return. However, the radar mounted on a ship is only suited for detecting the presence of an oil spill, but this radar is not suited for establishing the amount of oil spilled. Furthermore, this ship-mounted radar is only able to detect oil spills over distances of approximately 1 km. Accordingly, a single ship is capable of overlooking only a very small area. Hence, it necessary to use several ships in order to be able to detect the oil spill at an early stage and it is also necessary to have the ships at sea all the time.
Other techniques have been used to detect oil spills in rivers and in-land bodies of water where the use of aircraft and ships would not be practical, for example, due to noise abatement or shallow bodies of water. One such technique uses a combination of radar and a microwave radiometer mounted on a bridge over a river, so that the radar and the microwave radiometer look vertically down on the water as it flows under the bridge. It is difficult, however, to know where the sensors are to be mounted and it is uncertain if any bridges are available at the locations where the sensors are to be mounted. This necessitates specially fixed constructions such as wires across the river.
It can be seen then that there is a need for a method and apparatus for monitoring and measuring oil spills.